Question about replacing a bad drive

I have a quick question. Let’s say I have a 2 TB drive that has failed. If I want to replace it, for example with an 8 TB drive that has been used standalone previously, what happens if I insert the drive, and it already has content on it? If it were a normal RAID, I would automatically assume all data on the disk would be erased, but with Drobo, I wondered if it might be preserved?

It’s erased.

hi mystik, (if your question was just about erasing, then mgriffin has kindly answered)
though just in case you were actually also planning on using an 8tb drive in a drobo, please double check as some older models might not support it)